<template>
  <div class="app-container">
    <h2 style="text-align: center">发布新课程</h2>

    <el-steps
      :active="1"
      process-status="wait"
      align-center
      style="margin-bottom: 40px"
    >
      <el-step title="填写课程基本信息" />
      <el-step title="创建课程大纲" />
      <el-step title="最终发布" />
    </el-steps>

    <el-form label-width="120px">
      <el-form-item label="课程标题">
        <el-input
          v-model="courseInfo.title"
          placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"
        />
      </el-form-item>

      <!-- 所属分类 TODO -->
      <el-form-item label="课程分类">
        <el-select
          v-model="courseInfo.subjectParentId"
          placeholder="一级分类"
          @change="subjectLevelOneChanged"
        >
          <el-option
            v-for="subject in subjectOneList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"
          />
        </el-select>

        <!-- 二级分类 -->
        <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
          <el-option

            v-for="subject in subjectTwoList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"
          />
        </el-select>
      </el-form-item>

      <!-- 课程讲师 TODO -->
      <!-- 课程讲师 -->
      <el-form-item label="课程讲师">
        <el-select v-model="courseInfo.teacherId" placeholder="请选择">
          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"
          />
        </el-select>
      </el-form-item>

      <el-form-item label="总课时">
        <el-input-number
          :min="0"
          v-model="courseInfo.lessonNum"
          controls-position="right"
          placeholder="请填写课程的总课时数"
        />
      </el-form-item>

      <!-- 课程简介 TODO -->
      <el-form-item label="课程简介">
            <tinymce :height="300" v-model="courseInfo.description"/>
        </el-form-item>

      <!-- 课程封面 TODO -->
      <!-- 课程封面-->
      <el-form-item label="课程封面">
        <el-upload
          :show-file-list="false"
          :on-success="handleAvatarSuccess"
          :before-upload="beforeAvatarUpload"
          :action="BASE_API + '/eduoss/fileoss/upload'"
          class="avatar-uploader"
        >
          <img :src="courseInfo.cover" />
        </el-upload>
      </el-form-item>

      <el-form-item label="课程价格">
        <el-input-number
          :min="0"
          v-model="courseInfo.price"
          controls-position="right"
          placeholder="免费课程请设置为0元"
        />
        元
      </el-form-item>

      <el-form-item>
        <el-button
          :disabled="saveBtnDisabled"
          type="primary"
          @click="saveOrUpdate"
          >保存并下一步</el-button
        >
      </el-form-item>
    </el-form>
  </div>
</template>

<script>
import course from '@/api/edu/course'
import subject from '@/api/edu/subject'
import Tinymce from '@/components/Tinymce' //引入组件

export default {
    components: { Tinymce },
    data() {
        return {
            saveBtnDisabled: false,
            courseInfo:{
                        title: '',
                        subjectId: '',//二级分类id
                        subjectParentId:'',//一级分类id
                        teacherId: '',
                        lessonNum: 0,
                        description: '',
                        cover: '/static/01.jpg',
                        price: 0
                    },
                    courseId: '', //课程ID
                    BASE_API: process.env.BASE_API, // 接口API地址
                    teacherList:[],//封装所有的讲师
                    subjectOneList:[],//一级分类
                    subjectTwoList:[]//二级分类
        };
  },
  created() {
      //获取路由中的id值
        if(this.$route.params && this.$route.params.id){
            this.courseId = this.$route.params.id
            this.getInfo()
        }
      this.getTeacherList()
      this.getOneSubject()
  },
  methods: {
    getInfo() {
            course.getCourseInfoById(this.courseId)
                .then(response => {
                    //在courseInfo课程基本信息，包含 一级分类id 和 二级分类id
                    this.courseInfo = response.data.courseInfoVo
                    //1 查询所有的分类，包含一级和二级
                    subject.getSubjectList()
                        .then(response => {
                            //2 获取所有一级分类
                            this.subjectOneList = response.data.list
                            //3 把所有的一级分类数组进行遍历，
                            for(var i=0;i<this.subjectOneList.length;i++) {
                                //获取每个一级分类
                                var oneSubject = this.subjectOneList[i]
                                //比较当前courseInfo里面一级分类id和所有的一级分类id
                                if(this.courseInfo.subjectParentId == oneSubject.id) {
                                    //获取一级分类所有的二级分类
                                    this.subjectTwoList = oneSubject.children
                                }
                            }
                        })
                        //初始化所有讲师
                        this.getTeacherList()
                })
        },
    updateCourse(){
        course.updateCourseInfo(this.courseInfo)
          .then(response =>{
             this.$message({
                type: 'success',
                message: '修改课程信息成功'
              });
              this.$router.push({ path: "/course/chapter/"+this.courseId });
          })
    },
    addCourse(){
          course.addCourseInfo(this.courseInfo)
            .then(response => {
                this.$message({
                    type: 'success',
                    message: '添加课程信息成功!'
                });
                this.$router.push({ path: "/course/chapter/"+response.data.courseId });
            })
    },
    saveOrUpdate() {
      if(!this.courseInfo.id){
        this.addCourse()
      }else{
        this.updateCourse()
      }
       
    },
    getTeacherList(){
        course.getTeacherList()
            .then(response => {
                this.teacherList = response.data.items
            })
    },
    getOneSubject(){
        subject.getSubjectList()
            .then(response => {
                this.subjectOneList = response.data.list
            })
    },
    //点击某个一级分类，触发change，显示对应二级分类
    subjectLevelOneChanged(value){
        // value就是一级分类id值
        for(var i = 0; i < this.subjectOneList.length; i++){
            var oneSubject = this.subjectOneList[i]
            if(value === oneSubject.id){
                this.subjectTwoList = oneSubject.children
                //每次改完一级分类，清空二级分类id值
                this.courseInfo.subjectId = ''
            }
        }
    },
    //上传封面成功之前调用
    handleAvatarSuccess(response, file){
        this.courseInfo.cover = response.data.path
    },
    //上传前调用
    beforeAvatarUpload(file){
        const isJPG = file.type === 'image/jpeg'
        const isLt2M = file.size / 1024 / 1024 < 2
        if(! isJPG){
            this.$message.error('上传的图片只能是jpg格式！')
        }
        if(! isLt2M){
            this.$message.error('上传的图片大小不能超过2MB！')
        }
        return isJPG && isLt2M
    }
  },
};
</script>

<style scoped>
.tinymce-container {
  line-height: 29px;
}
</style>